/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.visualization;

import java.util.HashSet;
import java.util.Set;

import org.neo4j.graphdb.Entity;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.walk.Visitor;

/**
 * Traverses a graph and outputs the result to an external receiver.
 * @param <E>
 *            A base exception type that can be thrown by the methods of this
 *            visualizer.
 */
public class Visualizer<E extends Throwable> implements Visitor<Void, E>
{
    private final GraphRenderer<E> renderer;
    private final Set<Relationship> visitedRelationships = new HashSet<>();
    private final Set<Node> visitedNodes = new HashSet<>();

    /**
     * Creates a new visualizer.
     * @param renderer
     *            An object capable of rendering the different parts of a graph.
     */
    public Visualizer( GraphRenderer<E> renderer )
    {
        this.renderer = renderer;
    }

    public Void done() throws E
    {
        renderer.done();
        return null;
    }

    public void visitNode( Node node ) throws E
    {
        if ( visitedNodes.add( node ) )
        {
            renderProperties( renderer.renderNode( node ), node );
        }
    }

    public void visitRelationship( Relationship relationship ) throws E
    {
        if ( visitedRelationships.add( relationship ) )
        {
            renderProperties( renderer.renderRelationship( relationship ),
                relationship );
        }
    }

    public Visitor<Void, E> visitSubgraph( String name ) throws E
    {
        return new Visualizer<>(renderer.renderSubgraph(name));
    }

    private void renderProperties( PropertyRenderer<E> propertyRenderer, Entity entity ) throws E
    {
        for ( String key : entity.getPropertyKeys() )
        {
            propertyRenderer.renderProperty( key, entity.getProperty( key ) );
        }
        propertyRenderer.done();
    }
}
